Fuel injection system



Oct. 24, 1961 T. M. BALL 3,005,443

FUEL INJECTION SYSTEM Filed Aug. 13, 1958 v 4/ f -.!f-' INVENTOR.

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E a 7 BY W M Ma 3,005,448 FUEL INJE TION SYSTEM Thomas M. Ball,Bloomfield Hills, Mich, assignor to Chrysler Corporatiomllighlandflark,Mich, a corporation ofDelaware Filed Aug. 13,1958,- Ser.No.-754,766 11Claims. ((31.123-119) This invention relates to fuelasystems for;internal combustionengineslandin particular to thetype disclosed in therelated copendingapplication of ,ThomasM. Ball et al., Serial No.75l,'999,--filed luly 3-0, 1958, and assigned to applicants assignee.

In fuel systems for internaltcombustionengines-which utilize fuelpressure responsive fuel metering means to supply metered fuel to .arosette or fuel distribution chamber, the presencerof fuelvaporintheconduits of the system creates a serious'fuelsupply problem.Fuel vapor in the conduits occupying amuchlarger volume than liquidfuel, will cause a falseor synthetically produced pressure signal to betransmittedztowthe'aforementioned pressure responsive fuel meteringmeansand result in an erroneous adjustment-thereof. This erroneous adjustmentnecessarily causes an'incorrcct amount of fuel to flow to the engine.Moreover, fuel vapor in the distribution chamber prevents the chamberfrom properly distributing the metered liquid fuel in equal proportionsto the several cylinders of the engine. This unequal distributionresultsfrom the inability of the fuel distribution chamber distinguish between.vapor and liquid fuel and results in poor engine performance since somecylinders will be too rich in liquid fuel and other cylinderswill be toolean in liquid. fuelfor proper combustion eificiency andpowerdevelopment.

The aforementioned fuel vapor is produced mainly during operatingconditions of light engine load and high temperatures atwhich conditionsthe tendencyof the fuel to vaporize effectively exceedsits condensationtendency. By substantially increasing the pressure of the fuel in thelines of the system' and in the distribution chamber little fuelvaporwillfo-rm in the conduits regardlessiof the engine load andoperating temperatures.

This increase in fuel pressure is'brought about herein bythe provisionof a fuel nozzle which has an air bleed valve responsive to the existingmanifold pressure to. control the pressure drop across-the fuel outletof the system by increasing the fluid pressure immediately downstream ofsaid fuel outlet. "The valve is designed to allow a greater air bleed athigh vacuum manifoldconditions to offset the fuel drag out effect .Ofalargepressure drop across said fuel outlet. This valve and air bleedare also designedto effect thedirect'impingement of the bleed airupontheifuel'flowing through theiiuel outlet so as to uti-lize themomentum of the airrnoleculesin further reducing the pressure dropacross said fuel outlet.

An object of this invention is to providea fuel system for internalcombustion engines which system operates at fue'l pressuresrsufiicientto avoideXcess-ive fuel vaporization within the conduits and pass-agesof said system during light load andhigh temperature operatingconditions.

Anotherobject is ,ioprovidea fuel nozzle for use on fuel sy tte-msofinternal -,combustion engines which is responsive to variationsinthefuelrequirements of said engineto maintain the fuelpressure.within. said system sufliciently hig .Io preventusaid aforementionedfuel vaporization.

Patented Oct. 24, 1951 Another object is to provide a fuel,injectiounozzlefor usein :a fuel injection systemhavingia load meteringportion, a speed metering portion, and a fuel distribution portion,which nozzle is responsive to variations in the fuel. requirements ofsaid engine to maintain the pressure. of the fuel within said loadmetering portion, said speedmeteriug, portion, and said. fueldistribution portion of said system to prevent the aforementioned fuelvaporization.

.A further object isto provide an. effective means :to prevent theimproper distribution of fuel to the separate cylinders of amulticylinder internal. combustion engine due to fuel vaporizationwithinthe fuel system-feeding said engine.

Further-objects and advantages will become apparent from the followingspecificationand dnawings, in-which FiGURE 1 represents a view partly incrosssection of the complete fuel injection system; and

' FIGURE 2 represents an enlarged view in-cross section of thenfuelinjection nozzle shown in FIGURE 1.

In FIGURE liisshown -a=;fuel injection rneter-ingsysrem for an internalcombustion engine 10, said engine having heads 12 and exhaust manifoldbanks 14 oneach head thereof, said metering system comprising a fuelspeed metering unitld, a fuel load metering unit 18, and a fuel supply20. 'Thefuel speed-metering unit l6-is provided with four housingportions 22, 24, 26, and 28 separated from each other by diaphragms '30,32,- and 84 respectively to provide chambers 36, 38, 40, and 42. Chamber36 communicates withfuel supply 20 through conduit 44. A fuel pump 46 insaid conduit supplies a constant volume of fuel through filter 48 tochamber 36 during the operation of said engine regardless of the engineload or speed. A return flow metering orifice 50 in said housing portion22 connects chamber 36 with-'a return flow conduit 52 which communicateswith the inlet, check valve 54 of accelerator pump 30.

A return flow metering needle 56 having a'tapered point 58 is secured toeach of said diaphragms '30, 32, and 34 by suitable-grommets 60.

A flyweight support 62 pivotally supportsflyweights 64 and 66 and issecured to a flexible shaft '68 journaled, in housing 28 and operativelyconnected to the engine 10 to rotate at a speed directly proportional toengine speed.

Flyweights '64 and 66 have projections 70 and 72 reto rotation of shaft68 to urge needle '56 towardorifice 5.0 against the force applied in theopposite direction against diaphragm 30 by the fuel in chamber 36.

A conduit 74 connects chamber 36 to the upstream chamber 76 of the loadsensor 18 which upstream chamber communicates with a downstream fueldistribution chamber '78 of the load sensor across a load meteringorifice 80. A tapered load metering needle 82 having a tapered end84-positioned in orifice is operatively connected to piston'86reciprocably mounted in cylinder 88, which cylinder operativelycommunicates with each intake manifold on said engine through conduit92. Low pressure transmitted through conduit 92 will cause piston 86 tobe drawn upwardly against the force of spring 94 to thereby urge thetapered end of needle 82 into closer proximity to the sides of orifice80 and conversely high pressure in the intake manifolds will tend tourge needle '82 to amore open position with respect to orifice 80. Aplurality of nozzle feed conduits 9.6 extend from chamber 78 ofthe loadsensor to an equal number of fuel injection nozzle 98 located downstreamof the V 3 throttle valve 100 of the common intake manifold section 101.Chamber 78 of the load sensor is connected to chamber 38 of the speedsensor by conduit 112 to provide an adjustment of the return flowmetering needle 56 with respect to orifice 50 based on the pressuredifferential existing across orifice 80 of the load sensor.

An idle boost conduit 114 communicates with said common manifold section101 at a point adjacent the edge of the throttle valve 160 of thatsection and with the idle boost chamber 40 of the speed sensor. An airbleed valve 116 in conduit 114 is provided to regulate the pressuretransmitted to chamber 40 from said manifold section during idling ofthe engine in order to regulate thereby the speed of the engine atidling. Under normal idling conditions the pressure in chamber 40 islower than in chamber 42 which is vented to the atmosphere throughorifice 115 and said pressure in chamber 42 tends to urge the needle 56toward orifice 50 to retard the flow of return fuel therethrough andprovide a sufficient fuel supply for idling. The requirement of thisadditional boost to needle 56 is due to the fact that at slow enginespeed the flyweights are not flung outwardly with sufiicient force tonegate the frictional resistance of the needle 56 to movement.

The operation of the fuel injection metering unit will be described inrelation to a change in static engine operating conditions, that is,constant engine speed and load. Under said static operating conditions,the combined forces exerted by flyweights 64 and 66 and the fuel inchamber '38 is balanced by the force exerted by the fuel in chamber 36and the return flow metering member 56 is maintained stationary at adistance away from orifice 50. In this static condition, the amount offuel deliveredto the distributing chamber 78 is constant and is equal tothe constant amount of fuel being delivered to the system by the pumpless the constant amount of fuel being returned to the fuel tank throughthe return flow conduit 52. if this static condition represents theengine during normal driving speed, the pressure in chamber 42 has nonoticeable efiect on the operation of the unit and may be disregarded.It is only during idling and very low engine speeds that the pressuredifferential across diaphragm 34 becomes significant.

As the throttle valve 1% is moved to a more open position by thedepression of the engine accelerator, an increase in manifold pressureis transmitted to the load sensor piston through conduit 92 and movessaid piston down to thereby move the load metering needle 82 to a moreopen position with respect to the load metering orifice 80. The pressuredifferential existing across said orifice is consequently decreased asmore fuel is allowed to flow into chamber 78. This decrease in pressuredifferential causes the flow through orifice 80 to deviate from thedesirable flow which is substantially directly proportional to enginespeed. To correct this condition and bring the pressure differentialacross said orifice up to a value where the flow of fuel therethrough issubstantially directly proportional to engine speed, the fuel pressurein fuel supply pressure chamber 36 and load sensor upstream chamber 76communicating therewith is increased. This increase in pressure isaccomplished by moving the return flow metering member 56 closer toorifice 50 by the increased force transmitted by the fly- Weights 64 and66 as the engine speed is increased and by the increased pressure inchamber 38 caused by the increased flow of fuel into the downstreamchamber 78 of the load sensor. When the forces transmitted by saidflyweights and the fuel in said chamber 38 once again balance the forcetransmitted in the opposite direction by the fuel in chamber 36, theflow of fuel through orifice 80 will be substantially directlyproportional to the speed of the engine and will correspond to the flowof air into the intake manifold.

Referring to FIGURE 2, nozzle 98 comprises a body 118 threadedlyreceived at 119 in intake manifold 90 4 and having a recess 12%) adaptedto receive nozzle feed conduit 96 and retain said conduit thereinthrough frictional engagement therewith. The fuel outlet 122 of nozzlefeed conduit '96 communicates with manifold through nozzle passage meansor chamber 124 and primary fuel jet 126 in body 118. This primary fueljet is sufliciently large to accommodate the required fuel flow to theengine at relatively low speeds and light loads, but, at high manifoldpressure operating conditions a secondary fuel jet 128 in body 118 isopened by the movement of the adjustable pressure responsive slidingvalve means 130 to the right in FIGURE 2. This movement of means 130 tothe right is caused by high pressure in manifold 90 being transmittedthrough a manifold pressure passage or conduit 132 in body 118 to thechamber 134 and flexible diaphragm 136. The combined high manifoldpressure and the pressure of spring 138 forces diaphragm 136 to theright into chamber 140 which chamber is vented to the atmosphere at 142.Chambers 134 and 140 are formed by diaphragm housing portions 135 and141 secured together at their peripheries by suitable means 143.

An air bleed valve generally designated 144 is comprised of the tworelatively movable parts body 118 and sliding valve member 130. Bore 121of any convenient shape in body 118 slidably receives member 130 of acomplementary shape with a suflicient side clearance to allow movementof member 130 in response to slight pressure variations in chamber 134.An air bleed aperture 146 in body 118 and an air passage 148 in member130 allow an air flow to air jet 150 in the end of passage 148 when saidaperture and passage become partially or fully registered with eachother.

Registration of aperture 146 and passage 148 occurs when a low pressureexists in manifold 90 and is transmitted to chamber 134 and diaphragm136 through manifold pressure passage or conduit 132 in body 118. Whensaid registration occurs, the low pressure in manifold 90 will cause airto flow through 146, 148, and 150, and into chamber 124 in an amountproportional to the degree of said registration. This air flow willincrease the pressure in chamber 124 to a value which will decrease thepressure drop across fuel outlet 122 and prevent excessive sucking. outof the metered fuel from conduit SP6 and distsribution chamber 78.Another effect of said air flow is that the air molecules flowingthrough jet 150 are directed against the fuel flow through outlet 122and the momentum associated with said air molecules tends to force saidfuel back into the conduit 96. The effect .of the reduction in pressuredrop across the fuel outlet is a fuel pressure increase in conduits 96and distribution chamber 78 which pressure increase prevents the fuel insaid conduits and chamber from vaporizing and causing unequaldistribution of metered fuel to the separate fuel injection nozzles 98and also prevents erroneous adjustment of the fuel metering means asaforesaid.

It is noted that the sliding valve member 130 is advantageously used tocontrol the flow of fuel through the secondary fuel jet 128 and the flowof air through air jet 150 and it is obvious that at certain manifoldpressures both the jet 128 and the air valve 144 will be partiallyopened and partially effective to perform their functions.

I claim:

1. In a fuel injection system for an internal combustion engine havingan intake manifold, said system having a fuel feed conduit for supplyingfuel to said engine, a fuel injection nozzle adapted to be mounted insaid manifold, said nozzle comprising a body having means thereon forreceiving the fuel outlet end of said fuel feed conduit, fuel conduitmeans in said body operatively connecting said fuel outlet end to saidmanifold, adjustable air bleed means on said body communicating with theatmosphere and said fuel outlet end and operable to regulate thepressure drop across said fuel outlet end, and manifold pressureresponsive means operatively connected to said air bleed means-andsaidmanifold toaadjust-rsaidaair bleed means according to, manifold.pressure.

2. In a fuel system for a multicylinder internalcombustiongenginelhaving separate, intake; manifold ;.p.ortions communiating w h separate pylindfls .ofsaid engine, fuel e m ans cemmunicatnawith .said mani l PQYfiQIlS, -fue n z 'ineachisaid manifold-portionreceiv nais i fuel feed means, each said nozzle having fuel feedpressure regulating means thereon responsive to engine intake pressureto reduce the excessive drag out of fuel from said fuel feed meanscaused by low intake pressure and to maintain sufficient pressure insaid fuel feed means to prevent substantial fuel vaporization therein.

3. In a fuel injection system for an internal combustion engine havingan intake manifold, a fuel feed conduit connected to a fuel supply andcommunicating with said manifold, a fuel injection nozzle in saidmanifold receiving said conduit, said nozzle having fuel feed conduitpressure regulating means thereon to reduce the excessive drag out offuel from said conduit caused by high intake manifold vacuum, and saidpressure regulating means communicating with said manifold and beingresponsive to high vacuum therein to reduce said drag out.

4. In a fuel injection system for an internal combustion engine havingan intake manifold, a fuel feed conduit connected to a fuel supply andcommunicating with said manifold, said conduit having a fuel outlet, afuel injection nozzle in said manifold receiving said fuel outlet ofsaid conduit, said nozzle having a fuel jet communicating with said fuelfeed conduit outlet through nozzle passage means, and an adjustable airbleed valve on said nozzle communicating with said nozzle passage means,said air bleed valve being connected to said manifold and responsive topressure therein to regulate the flow of air through said valve to saidpassage means.

5. In a fuel injection system for an internal combustion engine havingan intake manifold, a fuel feed conduit connected to a fuel supply andcommunicating with said manifold, said conduit having a fuel outlet, afuel injection nozzle in said manifold receiving said. outlet, saidnozzle having a 'fuel jet communicating with said fuel feed conduitoutlet through nozzle passage means, an adjustable air bleed valve onsaid nozzle communicating with said nozzle passage means, said air bleedvalve being connected to said manifold and responsive to pressuretherein to regulate the flow of air through said valve, an adjustablesecondary fuel jet on said nozzle communicating with said nozzle passagemeans, an adjustable pressure responsive fuel valve means connected tosaid manifold and engageable with said secondary fuel outlet, and saidpressure responsive fuel valve means being adapted to allow an increasedfuel flow to the manifold in response to a corresponding increase inmanifold pressure.

6. In a fuel injection system for an internal combustion engine havingan intake manifold, a fuel feed conduit connected to a fuel supply andcommunicating with said manifold, said conduit having a fuel outlet, afuel injection nozzle in said manifold receiving said outlet of saidconduit, said nozzle having a fuel jet communicating with said fuel feedconduit through nozzle passage means, an adjustable air bleed valve onsaid nozzle communicating with said nozzle passage means, said valvehaving an air jet disposed directly opposite said fuel outlet of saidfuel feed conduit, and said air bleed valve being connected to saidmanifold and responsive to pressure therein to regulate the flow of airthrough said valve and said air jet.

7. In a fuel injection system for an internal combustion engine havingan intake manifold, a fuel feed conduit connected to a fuel supply andcommunicating with said manifold, said conduit having a fuel outlet,fuel metering means in said fuel feed conduit, said metering meanshaving metered fuel pressure responsive means thereon adapted to adjustsaid metering means. and the fuel iiow therethrough in accordance withthe --pressure of .said metered fuel, a fuel injection nozzle in.saidmanifold receivingsaid fuel outlet of :said conduit, and: saidnozzle having. intake pressure responsive fuel pressure regulating meansthereon communicating withsaid fuel outlet to reduce the pressure.dro-p'betweensaid fuel .out-let and-said manifold at high manifoldvacuum to reduce the excessive drag out of fuel from said conduit.

8. In a fuel injection system for an internal combustion engine havingan intake manifold, a fuel feed conduit connected to a fuel supply andcommunicating with said manifold, said conduit having a fuel outlet,fuel metering means in said fuel feed conduit, said metering meanshaving metered fuel pressure responsive means thereon adapted to adjustsaid metering means in accordance with the pressure of said meteredfuel, a fuel injection nozzle in said manifold receiving said fueloutlet of said conduit, said nozzle having air bleed means thereoncommunicating with said fuel outlet of said conduit, and said air bleedmeans communicating with said manifold and being adjustable according tomanifold pressure to reduce the excessive drag out of fuel from saidconduit caused by high intake manifold vacuum.

9. In a fuel injection system for an internal combustion engine havingan intake manifold, a fuel feed conduit connected to a fuel supply andcommunicating with said manifold, said conduit having a fuel outlet,fuel metering means in said fuel feed conduit, said metering meanshaving metered fuel pressure responsive means thereon adapted to adjustsaid metering means in accordance with the pressure of said meteredfuel, a fuel injection nozzle in said manifold receiving said fueloutlet of said conduit, said nozzle having a fuel jet communicating withsaid fuel outlet of said conduit through nozzle passage means, and anadjustable air bleed valve on said nozzle having an air jetcommunicating with said nozzl passage means, said air bleed valve beingconnected to said manifold and responsive to pressure therein toregulate the flow of air through said air jet, said air jet beingpositioned directly opposite said fuel outlet of said conduit.

10. In a fuel injection system for an internal combustion engine havingan intake manifold, a fuel feed conduit connected to a fuel supply andcommunicating with said manifold, said conduit having a fuel outlet, afuel metering valve in said fuel feed conduit, said valve having meteredfuel pressure responsive means associated therewith adapted to adjustsaid metering valve in accordance with the pressure of said meteredfuel, a fuel injection nozzle in said manifold receiving said fueloutlet of said conduit, said nozzle having a primary fuel jetcommunicating with said fuel outlet of said conduit through nozzlepassage means, an adjustable air bleed valve on said nozzlecommunicating with said nozzle passage means, said air bleed valve beingconnected to said manifold and responsive to pressure therein toregulate the flow of air through said valve to said passage means, asecondary fuel jet on said nozzle communicating with said nozzle passagemeans, and an adjustable pressure responsive means connected to saidmanifold and communicating with said secondary fuel jet, said pressureresponsive means being adapted to regulate the fuel flow through saidsecondary fuel jet and to allow an increased fuel flow to the manifoldtherethrough in response to a corresponding increase in manifoldpressure.

11. In a fuel injection system for an internal combustion engine havingan intake manifold, a fuel feed conduit connected to a fuel supply andcommunicating with said manifold, said conduit having a fuel outlet,fuel metering means in said fuel feed conduit, said metering meanshaving metered fuel pressure responsive means thereon adapted to adjustsaid metering means in accordance with the pressure of said meteredfuel, a fuel injection nozzle in said manifold receiving said conduit,said nozzle having a fuel jet communicating with said outlet ofsaid'fuel feed conduit through nozzle passage means, and an adjustableair bleed valve on said nozzle communicating with said nozzle passagemeans through an air jet, said air bleed valve being connected to saidmanifold and responsive to pressure therein to regulate the flow of airto said passage, said air jet being disposed directly opposite said fuelfeed conduit outlet References Cited in the file of this patent UNITEDSTATES PATENTS Y Pringham Nov. 18, 1958

